Neurofibromatosis type 1 (NF-1) is a relatively frequent syndrome, with an estimated incidence of 1/3000 per year. Patients with NF-1 are at an approximately fourfold higher risk of developing tumors than the general population, most frequently gastrointestinal stromal tumors, central nervous system tumors and endocrine tumors. Pheochromocytoma may occur in about 1% of these patients.
Case report: We report a 56-year-old male presenting with fatigue and chronic headaches, attended at an endocrinology consult for adrenal gland incidentaloma detected on a chest-CT. Previous diseases: hypertension and class I obesity. Family medical history: two sisters with NF-1.
Abdominal-CT showed a 6 cm nodule on the right adrenal gland, with 72 Hounsfield unit density pre-contrast and delayed contrast washout. Laboratory findings were consistent with pheocromocytoma: 24-h urinary fractionated metanephrines 1389 μg/24 h (25312), 24-h urinary serotonin and 5-hydroxitriptophan 10.9 mg/24 h (05), 24-h urinary 5-hydroxyindoleacetic acid 9.74 mg/24 h (26). The other biochemical and hormonal tests as well as tumor markers were unremarkable. Several clinical diagnostic criteria of NF-1 were identified: >6 café-au-lait macules >15 mm in longest diameter, >2 neurofibromas, two first-degree relatives with NF-1; genetic testing was also preformed. The screening for additional endocrine and tumor disorders related with NF-1 was negative. The treatment with β-blockers (propranolol, 10 mg, b.i.d.) and alpha-blockers (phenoxybenzamine, 10 mg, b.i.d.) kept the patient asymptomatic. Right suprarenalectomy was successfully preformed and the anatomopathological examination of the surgical sample confirmed the diagnosis of pheochromocitoma.
Conclusion: Pheochromocytoma in genetic disorders is more commonly diagnosed at a younger age in asymptomatic patients, due to premature screening of related tumors. In this case, the lack of clinical follow-up allowed the development of a large tumor, however with benign characteristics and few symptoms, with successful medical and surgical treatment.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.